Loop antenna



April '14, 1931- J. H. PRESSLEY 1,800,750

r LOOP ANTENNA Original Filed Nov. 15, 1925 of wave Zireciiov cy Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE LOOP ANTENNA Original application filed November 18, 1925, Serial No. 68,886. Patent No. 1,747,262, dated February 18,

1930. Divided and this application filed July This invention relates to a novel improvement in coils, used as antennae in radio communication apparatus, and has for one of its objects to provide means whereby the directional characteristic of a loop antenna may more nearly approximate the ideal figure 8 diagram, the present application being divisional from my copending application relating to improvements in loop 10 antenna, Serial No. 68,886, filed Nov. 13, 1925, Patent No. 1,747,262, dated February 18, 1930.

A more particular object of my invention is to provide a means whereby the displacement current effect of a solenoidal or box type of loop antenna may be eliminated.

With the foregoing and other objects in View the invention consists in the novel combination of parts hereinafter described and claimed, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatical sketch of my improved device for eliminating the dis- 535 placement current effect.

Fig. 2 is a top plan view of that shown in Fi 1.

l teferring more particularly to the drawings, in Fig. 1, a double layered loop is shown with the plane of the loop in the plane of the paper and YY is the vertical axis about which the loop may be rotated.

.Fig. 2 is a schematic view looking down on the top of the loop. For convenience in following the diagram, the outer turns are shown in solid lines and the inside turns in 24, 1926. Serial No. 1%,661.

conditions it is evident that e and e representing the displacement voltages induced in layer 1, will be neutralized by e and e, which represent the displacement voltages in layer 2. The above is on the premise that layers It 1 and 2 have the same number of turns of the same numerical pitch. It is obvious that to those skilled in the art, other arrangements and connections of the individual sections will present themselves, and that the same scheme may be employed with a loop of more than two layers, but it will in general be found preferable to use only an even number of layers.

Having thus described my invention, I '5 claim:

1. A loop antenna having an even number of layers and sections, the windings of alternate sections being of opposite pitch and so connected that the displacement current effeet in said sections substantially mutually neutralize each other, said sections also being so connected that the loop antenna has maximum self-inductance.

2. In a loop antenna having an even number of layers, the windings of alternate layers being of opposite pitch, the method of so connecting said layers that any displacement voltages induced therein are substantially mutually neutralized, and so that said loop an antenna has maximum self-inductance.

In testimony whereof I afiix my signature.

JACKSON H. PRESSLEY.

dotted lines with 1 as the outer layer and 2 as the inner layer, having connections 3 and 4.- between the inner and outer layers, and terminal leads 5 and 6. The space 8 is left to provide room for the mounting shaft, although the shaft maybe mounted in other ways if desired. The sections of the loop are so wound that the loop self-inductance is a maximum when the sections are connected as shown. In other words, the winding direction or pitch of the turns of the two sections of the outer layer must be the same, and of opposite pitch to the windin of the two sections of the inside layer. Un or these 

